[SOLVED] New PSU but same problem remains ?

[Darknoxx0]

A night or two ago while I was playing Valheim, my system all of a sudden powered down. I haven't installed any new hardware within the last several months so I assumed it might've been due to overheating. After the shut down I opened up the case and felt the back plate of my gpu, which was pretty hot to the touch. I didn't think much and waited 30 minutes before trying to turn it back on. Unfortunately, nothing happened, and my PC made no signs of power internally. After a bit of research, I assumed my PSU was the issue at fault and most likely died, even despite it being my gpu that I felt. I ended up troubleshooting a bit and used the PSU from my brother's PC to test. Bingo! It worked.

So since then I've purchased a new Seasonic Focus PSU, and just installed it.. but it still doesn't work. This time though, the lights and PSU fan flicker for a sec, before turning off immediately. The second time, absolutely nothing happened. I then unplugged everything except the 24-pin AC cable and tested if it was faulty (using the included test cap over the other end). For some reason, pressing in the hybrid-mode button is the only way for the Power supply fan to spin, unpressing the button will only result in a small twitch from the fan (I could be wrong, but I figured hybrid mode was only active when pressed, not the other way around, right?). So now I'm in a predicament, in which I don't know if I've just purchased a faulty PSU, or if my motherboard is ruined ?

Also, I started this thread in here instead of in Power Supplies as I am unsure just what's causing the problem.
My specs:

Z390 Aorus Pro Wifi Motherboard
i7-9700K @ 3.6ghz
Cooler Master Hyper 212 RGB Black
Gigabyte RTX 2070 Super
16gbs G.Skill Ripsjaws DDR4
Old PSU: Corsair CX750M Bronze
New PSU: Seasonic Focus GX-750 Gold

 

[rgd1101]

take the gpu out and test with igpu?

 

[geofelt]

I would not worry about heat coming from the graphics card.
They do run hot but they are designed to tolerate heat.
80c. under load is normal.

Those Seasonic power supplies are quite efficient and will not spin the fan unless necessary when using hybrid mode.
The purpose of a psu fan is to protect the psu under load, not for any sort of case cooling.

First, double check your psu connections to see that they are all secure.
Verify that the proper cables are inserted into the proper psu ports.
Use only the cables that came with the new psu.

If no joy, try your brother's psu again.
If that works, it is likely that your psu is defective. Not common, but it can happen.

I doubt that your motherboard has failed since at least one replacement psu worked.

 

[Darknoxx0]

I finally got everything to boot. I think the reason why it didn't when I used the new PSU was because my GPU and Drives were still using my old PSU power cables, so I had only plugged in the new cables into my CPU and Motherboard. I really didn't think this would of been the culprit, but apparently that was the case. Additionally, the hybrid function of the Seasonic PSU was active when unpressed, and the normal mode when pressed. I think they should rally switch that around in the future, but whatever. Anyway, thank you @geofelt for the simple suggestion of what the manual had highlighted in bold, I'll make sure to ONLY use new cables for future upgrades

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